mcyak

The thread on Velo-news had me excited.
Finally!
A compact double with 110 bcd pattern and...
the capability to go down to a 30t chainring.
Ahh the fly in the ointment.
Suginos site shows their 'new' compact double with a stepdown boss to utilize 74 bcd chainrings.
Immediately-upon seeing the boss I said to myself:"There's going to be issues trying to get the front derailleur to pull in and down far enough to make this feasable.

I'm wondering if anyone has one/has tried one with say; shimano ultegra or scram front derailleurs and if so, how'd it work.

And I ask the question (because suginos double smacks of TAs old touring triple setup)what the reason behind not simply offering doubles in 110 bcd and 30 or 32 t configurations?

HillRider

Actually a 110 BCD will accept down to a 33T chainring but a 30T requires a smaller BCD. The 74 mm BCD used on most road triples will take down to a 24T chainring.

Chris_W

What thread on Velonews are you talking about? I made a thread about this in the Long Distance Cycling subforum of BikeForums here. I'll repeat the important info: The outer ring BCD is 110mm, but the inner ring can either be a 110mm or 74mm BCD! Stock ring sizes offered will range from 30-46 to 36-52. It would actually be possible to use anything down to a 24-tooth inner ring because of the 74mm inner BCD, so you could even use it as a "touring double" with something like 26-42 rings.



Unfortunately, the price might be excessively high, at around US$500 - see replies to linked thread, although the only sources for prices found so far are in Asia, so I'm not sure about that.

As for what FDs will handle it, many people have used similar double-ring combinations (e.g., 30-46) on other cranksets and have had no problems using regular FDs - I'm currently running 28-46 rings on the inner two positions of a Truvativ Rouleur triple crank (74/130 BCD) and using a SRAM Rival FD without any problem.

What is unique about the Sugino crank is that there are no other cranks (AFAIK) that satisfy all of the following criteria:
1) Is designed to have only two rings (any triple crank can be used if the outer ring is left off and the space left empty, EDIT: or it could be replaced with a chainguard, as Velo Orange have done)
2) Allows something smaller than a 33-tooth inner ring
3) Has an integrated axle (if you don't care about that criterion, then a square-taper TA crank can be used with a 94mm BCD double spider, EDIT: or a White Industries VBC crank).
3) Has a road-bike chainline (i.e., around 43-45mm, other options that fit the first 3 criteria are all mountain bike cranks and so have a much wider chainline of 48-50mm), and subsequently also has a low Q-factor.

Using a setup like a 30-46 is basically the modern equivalent of the classic "half-step-plus-granny" gearing, which might have used chainrings like 28-44-48 and 5 to 7 cogs on the back. With 10-speed cassettes, the half-step gearing is no longer necessary to get a smooth progression through the gears, so only one large chainring is needed. Some people call such gearing a "super compact".

I ride long Alpine mountain passes all the time, so I need a small enough inner ring to keep a decent cadence (90+ rpm) with my modest power output, which means I need an inner ring with between 26 and 30 teeth (when using a road cassette with a largest cog of 26- to 28-teeth, I don't want to use a MTB cassette because the spacing between gears is too large). I then realized that having both a middle and big ring in addition to my inner was unnecessary, so I got myself a 46 tooth ring designed for the middle position of a triple (TA Specialites make one). In fact, before getting the TA 46 tooth ring, I tried it with a cheap single-speed 46-tooth ring to see if I liked the gear combinations I would have, and the shifting was still OK with that (partly because the single-speed ring was completely solid, heavy, and stiff, so it didn't bend at all when I tried to shift the chain onto it, so it didn't really need any pins or ramps).

Raiden

You guys might also look into the White Industries VBC crank. Cheaper, but uses proprietary chainrings.

fietsbob

V Orange is shipping a double , middle+ third, + a chainguard on the outer, now..

If 46-30 is the combo desired Right crank is a bit further outboard of course,
and spare 46t middles will be hard to replace , for spares..
as the outer 46 has the bolt head countersink on the other side..

TimeTravel_0

the inner ring on the VBC crank can be any 5 bolt chainring you want..hence the "VBC" name.

I do wish the outer ring came in silver.

Raiden

Yes, but you can also get the outer chainring in a huge variety of sizes, as there's no spider to limit it.

Just saying- it does the same thing as the Sugino crank, for <$300.

mcyak

https://forums.competitor.com/topic.php?id=2439 is hopefully the link to the post/thread on Velo News which I ran across while googling for compact cranksets offering lower than 34t.
I run a 46/33 setup on the stronglight compact I have on my 91 paramount.
The outer isn't ramped or pinned and does require a bit more time to load the chain onto the outer ring but..it's worked fine for 11K now.
My main concern was whether the shimano 6600 front derailleur and 10spd ultegra brifter setup would work well with the additional travel the 74 standoffs looked like they had.

mcyak

FWIW my origional post and subsequent on line investigating provided me with some good knowledge I didn't have prior to and some less expensive alternatives should I wish to trade out the compact FSA Team Issue on the Motobecane.
Many Thanks
)

Barrettscv 

Sram makes the XX double crankset for MTB, but it will work with a road drivetrain also. See: https://www.sram.com/truvativ/product...speed-crankset

The BCD is proprietary, so only Sram XX chainrings will work. It’s also a bit of an ugly duck, but the quality and performance should be great.

Michael

Chris_W

The XX crank does also come in a standard BB (not BB30) version. But the main problem I'd have with that crank (And any other MTB crank with integrated axle) is that the chainline would be too wide, which is not so appropriate to use with a road rear hub (although it would certainly be possible).

On the Sugino "Compact Plus" crank, having the inner ring mounted on the 74mm BCD instead of the 110mm shouldn't make any difference to the lateral movement needed by the FD - the inner ring should mount in the same plane regardless of the bolt circle used.

Chris_W

I noticed some people in the VeloNews thread thought that you could mount two rings on the 110mm BCD, and a third ring on the 74mm BCD. As mentioned on that thread, there are several problems with this: 1) It would require a lot of spacers and long bolts to mount the inner ring, which wouldn't be that strong of a setup. 2) The inner ring would be quite far inboard, so may not clear some chainstays. 3) The chainline would be off, making many cogs on the back inaccessible with the small ring without the chain rubbing on the middle ring. 4) The FD may not have enough lateral movement to shift down to the inner ring (so maybe this is the setup that you were talking about).

Mounting three rings on this crank is certainly not what Sugino are intending for you to do, and I think it would be a bad idea; there are many other triple cranksets out there that you can do that with. Admittedly, there now aren't many triple cranksets with 110/74mm BCDs being made, but look at the Stronglight Fission Triple for an integrated axle/external BB version, or a Stronglight Impact / Sugino XD (which are the same crank) for a traditional axle/internal BB version. Or, for a huge amount of cash, you could have a Stronglight X-Wing with three BCDs: 74, 110, and 146mm for the inner, middle, and outer rings, respectively (and it even comes in a BB30 version).

TimeTravel_0

what would be the "ideal" front derailleur for this crankset (or other wide-range compact doubles)? a front derailleur for a double or a triple? I'm sure both can work (esp. with friction front shifting), but which would probably shift better with a 18-20t difference? The triple, right?


vs

HillRider

Probably the triple would work better, not necessarily for shift speed or quality, but to allow the large difference in chainring diameters without the chain dragging on the the tail of the derailleur cage in the smallest chainring and some of the smaller cogs. The triple fd has a longer cage that wraps around the chainrings a bit further.

cs1

Can I do this to my Campy triple? I never use the 53T big ring. I'd love to have a 46/30 or something more useable.

AEO

if the rings are too small, they both might bottom out on the chainstay.

I've managed to setup a double FD to shift 26-36-46 sugino XD-600 triple decently.
IMO, using a barcon or campy ultrashift with MTB FD is a better solution.

fietsbob

Need a custom chainring if the pins and ramps are wanted,
as the counterbore for the bolt is on the wrong side for the usual outers

but if a plain chainring, and you allow time to make that big upshift, you can flip those,,

I got a campag triple in the 8os , 144 bcd and one of their big cross chainguards, 222 dia,
and have a very polished 52 36 combo ..

ITS FS .!

TimeTravel_0

so you're saying a mountain fd will be better than a road triple rd? why?

fietsbob

Potentially tail of FD hits the chainstay, when moving inward,
but is still too far above the larger chainring..
to shift properly

Chris_W

I use a double FD (SRAM Rival) to shift my 46-28 crankset, and it works well (operated by a down-tube shifter), but I've also previously used a triple FD (Ultegra) and that worked OK. My problem with the Ultegra FD was that I have a braze-on mounted FD, so to get the FD low enough for the 46 tooth big ring, I had to file down the mounting slot an extra couple mm. Unfortunately, that still wasn't enough, so I got the SRAM FD because it has two mounting holes, one of which allows you to place it pretty low down. No problems with chainstay clearance with my setup.

In response to the question about whether such a gearing combination can be achieved using a standard triple crankset, the answer is yes. My 46-28 rings are in the middle and inner positions of a 130/74 triple. 46 teeth is the largest ring you can get from TA Specialites that is designed for the middle position (130mm BCD, the difference between and outer and a middle ring is that the midde has the recessses for the mounting bolts on the inside). However, when I was first experimenting, I used a cheap singlespeed 46 tooth ring and I was very surprised how well that shifted without any gates or ramps (I think the stiffness of the solid chainring helped a lot). If you have a Campy triple crankset, it probably has a 135mm BCD for the middle and large rings, and so you may be more restricted in what rings are available for the middle position.

AEO

that and the curvature of a MTB FD is better shaped to take on the smaller diameter chainrings.
simply put, it's better designed for the smaller rings.

TimeTravel_0

any potential issues with the different chainlines and spacings of road vs. mountain bike when using a mountain fd on a road bike?

basically, a triple is not a good option...but a mountain fd and a double fd would the better choices?